I was going to ask the same question. I have tried Back to Basics Thickening Shampoo for men and Crew Thickening Shampoo for men, they both work good- but I would not say they are night and day improvements over regular shampoo. I saw the Vive by L'oreal at the store claims 50% thicker hair, also the product line called thicker fuller hair people say that is a good one.
Any suggestions are greatly appreciated.